Articular bone

The articular Os (Latin for " hinge leg," short form articular ) is a bone of the skull of fishes, amphibians reptiles and birds. Its articular surface (facies articular quadratica ) forms with the Os quadratum the primary jaw joint.

In mammals, the os is not articular trained. After the Reichert Gauppschen theory forms from the articular Os in mammals the malleus.